Single-crystal ternary cathode material, method for preparing the same, cathode plate, and battery

Abstract

This application discloses a single-crystalline ternary cathode material, a method for preparing the same, a cathode plate, and a battery, and belongs to the technical field of battery materials. The apparent factor Z of the single-crystalline ternary cathode material is Z = 【Equation 1】 JPEG2026522214000013.jpg13170, satisfying 1.1 ≤ Z ≤ 3, and x = D 90 / D 10 and satisfying 2 ≤ x ≤ 5, where S(D 90 ) is the number-average circularity. When the total number of target particles is n, the number-average circularity is the value obtained by dividing the sum of the circularities of all target particles by n. The area and perimeter corresponding to the two-dimensional projection diagram of each target particle are defined as S1 and l1, respectively, the perimeter of the circle having S1 is defined as l2, and the circularity = l2 / l1. H = 【Equation 2】 JPEG2026522214000014.jpg11170×100%, where D 10 ’ is the particle size of the material obtained by pressing the single-crystalline ternary cathode material at a pressure of 200 MPa, D 10 is 2.4 μm or less, and D 10 ’ is 2.3 μm or less. The single-crystalline ternary cathode material has a smooth surface, rounded edges and corners, and can contribute to the preparation of a battery with excellent electrochemical performance.

Description

[Technical Field]

[0001] This disclosure relates to the technical field of battery materials, and more specifically to single-crystal ternary cathode materials, methods for preparing the same, cathode plates, and batteries.

[0002] Cross-references of related applications This application claims priority based on a Chinese patent application filed with the China Patent Administration on May 24, 2024, with application number 202410651224.2, titled "Single-crystal ternary cathode material, method for preparing the same, cathode plate and battery," the entire contents of which are incorporated into this application by reference. [Background technology]

[0003] Currently, ternary cathode materials are typically polycrystalline secondary particles formed by the aggregation of nano-sized primary particles. During the charge-discharge cycle, the volume of the unit cell of these primary particles changes, resulting in anisotropic stress distribution within the secondary particles. This causes grain boundary cracking in the polycrystalline secondary particles, ultimately leading to the pulverization of the polycrystalline particles. Furthermore, preparing electrode plates for cathode materials requires roll rolling, and the aggregated polycrystalline secondary particles are easily pulverized by rolling, impairing the battery's cycle life and limiting the commercialization of batteries.

[0004] Single-crystal ternary cathode materials consist of independent micro-sized particles, possess relatively high mechanical strength, are less prone to pulverization during the roll rolling process of electrode plates, and exhibit superior cycle stability without grain boundary cracking during charge-discharge cycles. They are high-performance cathode materials that have the potential to replace some polycrystalline ternary cathode materials.

[0005] Single-crystal materials can typically be obtained by a common preparation method that involves mixing hydroxide precursor secondary particles with a lithium source, followed by high-temperature sintering and then air-jet grinding. However, in the above process, aggregated particles are forcibly separated, resulting in the creation of sharp edges and corners. These sharp edges and corners can cause at least one of the following problems.

[0006] (1) In the process of preparing the battery electrode, it causes serious wear to the equipment, shortens the service life of the equipment parts, and greatly increases the manufacturing cost of the battery. (2) In the roll rolling process of preparing the electrode plate, particles with sharp edges or corners are more likely to crack, causing single crystal layer peeling and surface defects, and forming more fine powder particles. (3) Sharp edges or corners cause non-uniform charge and discharge of the material during the charge and discharge process of the battery, resulting in a relatively strong polarization effect. As a result, particle pulverization occurs due to stress during the cycle process, and the life of the battery is rapidly shortened. (4) When performing surface coating on single crystal materials, it is difficult to completely coat sharp edges or corners, which impairs the coating effect and cannot improve the cycle performance.

[0007] In view of this, the present disclosure is provided.

Summary of the Invention

[0008] The present disclosure aims to provide a single crystal ternary cathode material, a preparation method thereof, a cathode plate, and a battery that can solve or improve at least one of the above technical problems.

[0009] The present disclosure is realized as follows.

[0010] In a first aspect, the present disclosure provides a single crystal ternary cathode material. The apparent factor Z of the single crystal ternary cathode material is Z =

Number

Number

[0011] In a selectable embodiment, the single-crystalline ternary cathode material Feature 1: D 90 of the single-crystalline ternary cathode material is 8.6 μm or less, Feature 2: H of the single-crystalline ternary cathode material is 80% or more, Feature 3: S(D 90 ) of the single-crystalline ternary cathode material is 0.9 or less, and includes at least one of Features 1 to 3 above.

[0012] In a selectable embodiment, the apparent factor of the single-crystalline ternary cathode material is 1.1634 to 2.9571, and / or x of the single-crystalline ternary cathode material is 2.36 to 3.88, and / or D of single-crystal ternary cathode materials 90 The size ranges from 5.01 μm to 8.56 μm. and / or D of single-crystal ternary cathode materials 10 The size is 1.81 μm to 2.34 μm. and / or, the H content of the single-crystal ternary cathode material is 81% to 96%, and / or S(D) of single-crystal ternary cathode materials 90 ) is 0.68~0.87, and / or D of single-crystal ternary cathode materials 10 The size is between 1.57 μm and 2.25 μm.

[0013] In an optional embodiment, the single-crystal ternary cathode material is Feature 4: The particle size of the single-crystal ternary cathode material is 20 μm or less, Feature 5: The general formula for single-crystal ternary cathode materials is Li d Ni a Co b M c M' 1-a-b-c The O2 satisfies 0.95≦d<1.1, a>0, b>0, c>0, and 0.95≦(a+b+c)≦1, where M includes at least one of Al and Mn, and M' includes at least one of a doping element and a coating element, where the doping element and coating element are each independently at least one selected from Zr, Sr, Mo, Ba, W, B, Ti, Mg, Li, C, F, Si, Ca, Cu, La, P, Ce, Bi, In, Nb, and Y. Feature 6: In a single-crystal ternary cathode material, the unit cell parameter c and the unit cell parameter a satisfy c / a ≥ 4.899, Feature 7: (003) crystal plane diffraction peak intensity I of single-crystal ternary cathode material (003) (104) Crystal plane diffraction peak intensity I (104) However, I (003) / I (104) The condition that ≥ 1.51 is met, Feature 8: The electrode plate corresponding to the single-crystal ternary cathode material has a surface roughness Ra of 2.20 μm or less, It further includes at least one of features 4 through 8.

[0014] In an optional embodiment, the doping reagent providing the doping element comprises at least one of the oxides, fluorides, carbonates, hydroxides, nitrides, borides, and nitrates corresponding to the doping element. and / or, the coating reagent providing the coating element comprises at least one of the oxides, fluorides, carbonates, hydroxides, nitrides, borides, and nitrates corresponding to the coating element.

[0015] In selectable embodiments, the surface roughness Ra of the electrode plate corresponding to the single-crystal ternary cathode material is 0.86 μm to 2.12 μm.

[0016] In a second embodiment, the present disclosure provides a method for preparing a single-crystal ternary cathode material according to any one of the embodiments described above. The preparation method is as follows: The first step involves mixing a precursor of a single-crystal ternary cathode material with a first lithium source, followed by a first firing to obtain a first mixture. The first mixture is rapidly transferred to water at a high temperature and stirred to perform the first grinding, thereby obtaining the second mixture. The second mixture and the second lithium source are mixed, and then a second firing is performed to obtain the third mixture. The process includes the step of performing a second grinding of the third mixture to obtain a fourth mixture.

[0017] In an optional embodiment, the preparation of the first mixture is as follows: Feature 1: The type of precursor for the single-crystal ternary cathode material is a hydroxide precursor, Feature 2: The ratio of the total molar amount of transition metal elements in the precursor of the single-crystal ternary cathode material to the molar amount of lithium element in the first lithium source is 1:0.4 to 1:0.7, Feature 3: The temperature of the first firing is 650°C to 750°C, Feature 4: The first firing time is 1 to 3 hours, Feature 5: The first firing is carried out in an oxygen-containing atmosphere, It includes at least one of the characteristics 1 to 5.

[0018] In an optional embodiment, the precursor of the single-crystal ternary cathode material comprises nickel-cobalt-manganese hydroxide or nickel-cobalt-aluminum hydroxide.

[0019] In an optional embodiment, the first grinding is performed as follows: Feature 6: The first pulverization is achieved by the thermal expansion effect, Feature 7: The water temperature used for the first grinding must be above 0°C and below 50°C. Feature 8: The rotation speed of the first grinding and stirring is 100 rpm to 200 rpm, Feature 9: The stirring time for the first grinding is 5 to 20 minutes, It includes at least one of features 6 to 9, And / or, the second grinding is carried out using an air-jet grinding method.

[0020] In an optional embodiment, the time for transferring the first mixture to water at a high temperature is 30 minutes or less.

[0021] In an optional embodiment, the preparation of the third mixture is as follows: Feature 10: The ratio of the total molar amount of lithium element in the first and second lithium sources to the total molar amount of transition metal element in the second mixture is 1.05:1 to 1.1:1, Feature 11: The temperature of the second firing is 800℃ to 950℃, Feature 12: The second firing time is 4 to 6 hours, Feature 13: The second firing is carried out in an oxygen-containing atmosphere, It includes at least one of the features 10 to 13.

[0022] In an optional embodiment, if the single-crystal ternary cathode material contains a doping element, a first calcination is performed after mixing the precursor of the single-crystal ternary cathode material, a first lithium source, and a doping reagent that provides the doping element, or a second calcination is performed after mixing the second mixture, a second lithium source, and a doping reagent that provides the doping element. Alternatively, if the single-crystal ternary cathode material contains a coating element, the preparation method further includes mixing the fourth mixture with a coating reagent that provides the coating element, followed by a third firing.

[0023] In an optional embodiment, the oxygen content in the oxygen-containing atmosphere during the first firing is 20 wt% or more, and / or the second firing is performed in an oxygen-containing atmosphere with an oxygen content of 20 wt% or more, and / or the third firing is performed in an oxygen-containing atmosphere with an oxygen content of 20 wt% or more. In a third embodiment, the disclosure provides a cathode plate in which the active material comprises a single-crystal ternary cathode material according to any one of the embodiments described above.

[0024] In a selectable embodiment, the positive electrode plate is Feature 9: The initial discharge ratio capacity at 0.1C corresponding to the positive electrode plate is 171.0 mAh / g or higher, Feature 10: The capacitance retention rate after 50 cycles at 0.1C for the positive electrode plate is 89.2% or higher, Feature 11: The initial discharge ratio capacity at 1C corresponding to the positive electrode plate is 148.3 mAh / g or higher, Feature 12: The initial discharge ratio capacity at 5C corresponding to the positive electrode plate is 125.8 mAh / g or higher, It includes at least one of the features 9 to 12.

[0025] In a fourth embodiment, the disclosure provides a battery cell, which includes a positive electrode plate according to the above embodiment.

[0026] In a fifth embodiment, the present disclosure provides a battery, which includes a battery cell according to the above-described embodiment.

[0027] In a sixth embodiment, the present disclosure provides an electrical device, which includes a battery cell or battery according to the above embodiments.

[0028] In selectable embodiments, the electrical device includes a mobile phone, tablet, laptop computer, electric toy, power tool, electric car, electric vehicle, ship, or aircraft.

[0029] This disclosure has the following beneficial effects:

[0030] This disclosure provides a single-crystal ternary cathode material having apparent factors that satisfy a specific range. This single-crystal ternary cathode material has a smooth surface and rounded edges and corners, which can contribute to electrodes using this cathode material having relatively high specific capacity, rate performance, and cycle performance. The preparation method for a suitable single-crystal ternary cathode material is simple, easy to operate, and suitable for mass production. Using the above-mentioned single-crystal ternary cathode material, batteries and electrical devices with excellent electrochemical performance can be prepared.

[0031] To more clearly explain the technical concepts of the embodiments of this disclosure, the drawings used in the embodiments are briefly described below. The drawings described are merely illustrative of some embodiments of this disclosure and do not limit the scope. Those skilled in the art can obtain other relevant drawings based on these drawings without inventive ability. [Brief explanation of the drawing]

[0032] [Figure 1] These are the XRD patterns of the single-crystal ternary cathode materials obtained in each of the experimental examples, Examples 1-5 and Comparative Example 1. [Figure 2] These are SEM images of single-crystal ternary cathode materials obtained in each of the experimental examples, Example 1, Example 10, and Comparative Example 1. [Figure 3]This graph shows the relationship between the apparent factor of the single-crystal ternary cathode material obtained in each of the experimental examples, Examples 1-13 and Comparative Examples 1-4, and the surface roughness of the electrode plate corresponding to each single-crystal ternary cathode material. [Modes for carrying out the invention]

[0033] To more clearly explain the purpose, technical proposals, and advantages of the embodiments of this disclosure, the technical proposals in the embodiments of this disclosure will be described clearly and completely below. Where specific conditions are not specified in the embodiments, it is possible to perform the experiments under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments where the manufacturer is not specified, commercially available conventional products can be used.

[0034] The terms "and / or" as used in this specification represent a relationship between related objects, indicating that three types of relationships exist. For example, A and / or B represents three types of relationships: A exists alone, both A and B exist, and B exists alone.

[0035] The following describes in detail the single-crystal ternary cathode material, its preparation method, cathode plate, and battery related to this disclosure.

[0036] This disclosure provides a single-crystal ternary cathode material. The apparent factor Z of the single-crystal ternary cathode material is Z =

number

[0037] This disclosure provides a single-crystal ternary cathode material having apparent factors that satisfy a specific range. The single-crystal ternary cathode material has a smooth surface and rounded edges and corners, which can contribute to electrodes and batteries using this cathode material having relatively high specific capacity, rate performance, and cycle performance.

[0038] The apparent factors described above integrate several apparent indices (e.g., particle size distribution, particle morphology, and hardness) of a single-crystal ternary cathode material. These apparent indices are related to the press density of the single-crystal ternary cathode material, which in turn is closely related to the surface roughness and electrochemical performance of the electrode plate containing the single-crystal ternary cathode material. Generally, the higher the press density of the cathode material, the better the electrochemical performance of the electrode corresponding to that cathode material. Alternatively, the surface roughness of the electrode plate is also one of the factors that affect the performance of the electrode; the lower the surface roughness, the better the cycle performance of the electrode. Therefore, the apparent factors can be used to predict some of the performance of the cathode material and the electrode. For example, the apparent factors defined in this disclosure and the surface roughness of the electrode plate containing the single-crystal ternary cathode material have a linearly positive correlation.

[0039] The apparent factor of the above-mentioned single-crystal ternary cathode material is 1.1 to 3.0, and in several selectable forms, for example, 1.1634 to 2.9571, such as 1.1634, 1.1959, 1.3481, 1.5992, 1.6826, 1.7659, 1.7735, 1.7978, 1.9834, 2.1570, 2.2532, 2.5193, 2.8008, or 2.9571. A single-crystal ternary cathode material having an apparent factor that satisfies the above range allows a battery using this material as the cathode to achieve superior overall performance (including specific capacity, rate performance, and cycle performance).

[0040] x=D 90 / D 10 And satisfying 2 ≤ x ≤ 5, that is, x can be any value in the range of 2 to 5, for example, 2, 2.5, 3, 3.5, 4, 4.5 or 5. In several selectable forms, D of single-crystal ternary cathode material 90 / D 10 The value of is between 2.36 and 3.88, and can be, for example, 2.36, 3.22, 3.35, 3.55, 3.67, or 3.88.

[0041] D 90This is the particle size corresponding to the volume-based cumulative particle size distribution of a single-crystal ternary cathode material when it reaches 90%, and D 10 This represents the particle size corresponding to the volume-based cumulative particle size distribution of a single-crystal ternary cathode material when it reaches 10%.

[0042] In several selectable forms, D of single-crystal ternary cathode material 90 The particle size is 8.6 μm or less, and can be, for example, between 5.01 μm and 8.56 μm, such as 5.01 μm, 5.92 μm, 6.09 μm, 6.59 μm, 6.82 μm, 7.39 μm, 7.89 μm, or 8.56 μm.

[0043] In several selectable forms, D of single-crystal ternary cathode material 10 The particle size is 2.4 μm or less, for example, between 1.81 μm and 2.34 μm, and could be, for example, 1.81, 1.84, 1.92, 1.96, 2.02, 2.11, 2.15, or 2.34.

[0044] S(D 90 ) is the number-average circularity, and the target particle size in a single-crystal ternary cathode material is D 90 Assuming that the above is defined as a single-crystal ternary cathode material particle, and the total number of target particles contained in the single-crystal ternary cathode material is n, the number-average circularity is the value obtained by dividing the sum of the circularities of all target particles contained in the single-crystal ternary cathode material by n.

[0045] Let S1 and l1 be the area and perimeter corresponding to the two-dimensional projection of each target particle, respectively. Let l2 be the perimeter of a circle with area S1, and let Q = l2 / l1.

[0046] In several selectable forms, S(D) of single-crystal ternary cathode materials 90 ) is less than or equal to 0.9 and can be, for example, 0.68 to 0.87, such as 0.68, 0.70, 0.71, 0.73, 0.77, 0.79, 0.80, 0.82, 0.84 or 0.87.

[0047] The above D 90 , D 10 and S(D 90 A single-crystal ternary cathode material having the range of ) can contribute to improving the press density of electrodes containing the single-crystal ternary cathode material, reducing the surface roughness of electrode plates, and improving the electrochemical performance of electrodes and corresponding batteries, due to the effect of packing with a specific particle size distribution and the diverse contact modes of irregularly shaped powders (e.g., combinations of points, lines, and planes). 90 / D 10 This can reflect the particle size distribution range of the powder, and this D 90 , D 10 Powders having the above S(D) have a filling effect with a specific particle size distribution and can improve press density. 90 The powders within the specified range have irregular shapes, resulting in diverse contact patterns (e.g., combinations of points, lines, and surfaces). This improves contact between powders and contributes to increased press density, which in turn contributes to improved electrochemical performance of the electrode plates due to the relatively high press density.

[0048] H is hardness, and H =

number

[0049] In several selectable forms, D of single-crystal ternary cathode material 10 ' is 2.3 μm or less, for example, 1.57 μm to 2.25 μm, and can be, for example, 1.57 μm, 1.69 μm, 1.72 μm, 1.74 μm, 1.77 μm, 1.82 μm, 1.92 μm or 2.25 μm.

[0050] In several selectable forms, the H content of the single-crystal ternary cathode material is 80% or more, and can be, for example, 81% to 96%, such as 81%, 87%, 88%, 89%, 90%, 91%, 92%, or 96%.

[0051] In several selectable configurations, the particle size of the single-crystal ternary cathode material is 20 μm or less; that is, the particle size of the largest particle in the single-crystal ternary cathode material is 20 μm or less.

[0052] In several selectable forms, the general formula for single-crystal ternary cathode materials is Li d Ni a Co b M c M' 1-a-b-c The solution is O2, satisfying the following conditions: 0.95 ≤ d < 1.1, a > 0, b > 0, c > 0, and 0.95 ≤ (a + b + c) ≤ 1. The above values ​​of a, b, c, and d are all based on the number of moles, and their unit is moles.

[0053] M includes at least one of Al and Mn. That is, M may include only Al, only Mn, or both Al and Mn.

[0054] M' contains at least one of the doping element and the coating element. That is, M' may contain only the doping element, only the coating element, or both the doping element and the coating element. When a+b+c=1, the single-crystal ternary cathode material contains neither the doping element nor the coating element.

[0055] Exemplary, the doping element and coating element described above are each independently at least one selected from Zr, Sr, Mo, Ba, W, B, Ti, Mg, Li, C, F, Si, Ca, Cu, La, P, Ce, Bi, In, Nb, and Y. In some selectable forms, the doping element and coating element may be the same, and in some other selectable forms, the doping element and coating element may be different.

[0056] Exemplary, a doping reagent providing a doping element comprises at least one of the oxides, fluorides, carbonates, hydroxides, nitrides, boridides, and nitrates corresponding to the doping element. Similarly, a coating reagent providing a coating element comprises at least one of the oxides, fluorides, carbonates, hydroxides, nitrides, boridides, and nitrates corresponding to the coating element.

[0057] In several selectable forms, in single-crystal ternary cathode materials, the unit cell parameter c and the unit cell parameter a satisfy c / a ≥ 4.899, and can be, for example, 4.9174, 4.9234, 4.9375, 4.9425, or 4.9487. Single-crystal ternary cathode materials having the above c / a values ​​have good crystallinity and a highly ordered layered structure, and the crystal structure is relatively stable. Within the above range, the larger the c / a value, the better the layered structure of the material, and the greater the contribution to the insertion and deinsertion of lithium ions between layers.

[0058] In several selectable forms, the (003) plane diffraction peak intensity I of the single-crystal ternary cathode material (003) (104) Crystal plane diffraction peak intensity I (104) R=I (003) / I (104) The value must be ≥1.51, and may be, for example, 1.51, 1.62, 1.68, 1.74, or 1.87. The R value can be used to determine the degree of irregular arrangement of Li and Ni; the larger the R value, the lower the degree of irregular arrangement of the material, and the crystal structure of the material can be contributed to by the insertion and deinsertion of lithium ions.

[0059] In several selectable forms, the surface roughness Ra of the electrode plate corresponding to the single-crystal ternary cathode material is 2.20 μm or less, and can be, for example, 0.86 μm to 2.12 μm, such as 0.86 μm, 1.17 μm, 1.20 μm, 1.23 μm, 1.24 μm, 1.52 μm, 1.61 μm, 1.62 μm, 1.67 μm, 1.75 μm, 1.76 μm, 1.84 μm, or 2.12 μm. There is a linear correlation between the apparent factor and the surface roughness of the electrode plate according to this disclosure. The single-crystal ternary cathode material corresponding to the electrode having the above surface roughness is well-formed, smooth, and has few sharp edges or corners.

[0060] Accordingly, this disclosure further provides a method for preparing the above-described single-crystal ternary cathode material. The preparation method includes, for example, the following steps.

[0061] Step (1): The precursor of the single-crystal ternary cathode material and the first lithium source are mixed, and then the first calcination is performed to obtain the first mixture.

[0062] Step (2): The first mixture is ground once in water to obtain the second mixture.

[0063] Step (3): After mixing the second mixture with the second lithium source, a second firing is performed to obtain the third mixture.

[0064] Step (4): The third mixture is ground a second time to obtain the fourth mixture.

[0065] In several selectable forms, the type of precursor for the single-crystal ternary cathode material is a hydroxide precursor, which may be, for example, nickel-cobalt-manganese hydroxide or nickel-cobalt-aluminum hydroxide.

[0066] The ratio of the total molar amount of transition metal elements in the precursor of the single-crystal ternary cathode material to the molar amount of lithium in the first lithium source can be 1:0.4 to 1:0.7, for example, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, or 1:0.7, or any other value within the range of 1:0.4 to 1:0.7.

[0067] The temperature for the first firing may be between 650°C and 750°C, and may be, for example, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, 740°C, or 750°C, or any other value within the range of 650°C to 750°C.

[0068] If the temperature during the first firing is too low, the material may not crystallize, and if the temperature during the first firing is too high, the irregular arrangement of lithium nickel is likely to become severe.

[0069] The time for the first firing can be between 1 and 3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours, or any other value within the range of 1 to 3 hours.

[0070] The first firing may be carried out in an oxygen-containing atmosphere. Exemplarily, the oxygen content in the oxygen-containing atmosphere may be 20 wt% or more, for example, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 100 wt%. In several selectable configurations, the oxygen content in the oxygen-containing atmosphere is 80 wt% or more.

[0071] In the preparation process of single-crystal ternary cathode materials, the first grinding is achieved by the effect of thermal expansion. For example, the first mixture obtained from the first firing is rapidly transferred to water under high temperature conditions. For reference, the transfer time is 30 minutes or less. Since the temperature of the first mixture obtained from the first firing is relatively high and the temperature of the water is 0°C to 100°C, if the first mixture is transferred to water within the above transfer time, a thermal expansion effect occurs in the first mixture, and by adding stirring, grinding can be effectively achieved. Performing the first grinding using this method results in relatively mild grinding conditions, improves the smoothness of the ground material, and reduces or prevents the formation of sharp edges and corners. Furthermore, performing the first grinding using this method helps to remove lithium hydroxide remaining on the surface of the first mixture obtained from the first firing. As a result of the first grinding, the material can be ground more thoroughly, contributing to improved elemental dispersibility, shortening the time for the second firing, and thereby contributing to the reduction of irregular arrangement of lithium nickel.

[0072] In several selectable configurations, the temperature of the water used for the first grinding is greater than 0°C and less than or equal to 50°C, and may be, for example, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C, or any other value within the range greater than 0°C and less than or equal to 50°C.

[0073] The first grinding is carried out under stirring conditions. For example, the stirring speed may be 100 rpm to 200 rpm, such as 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, or 200 rpm, or any other value within the range of 100 rpm to 200 rpm. The stirring time may be 5 minutes to 20 minutes, such as 5 minutes, 10 minutes, 15 minutes, or 20 minutes, or any other value within the range of 5 minutes to 20 minutes.

[0074] In some selectable forms, the second grinding may be carried out by air-jet grinding, and in some other embodiments, the second grinding may be carried out by other means.

[0075] In several selectable configurations, the ratio of the total molar amounts of lithium elements in the first and second lithium sources to the total molar amounts of transition metal elements in the second mixture can be between 1.05:1 and 1.1:1, for example, 1.05:1, 1.06:1, 1.07:1, 1.08:1, 1.09:1, or 1.1:1, or any other value within the range of 1.05:1 to 1.1:1.

[0076] When preparing single-crystal ternary cathode materials, an excess lithium source is required. This disclosure realizes the addition of the lithium source by adding lithium in two stages. By setting the ratio of the total molar amount of lithium element in the first and second lithium sources to the total molar amount of transition metal element in the second mixture to 1.05:1 to 1.1:1, it is possible to prevent the residue of a relatively large amount of lithium hydroxide due to an excess of the total amount of lithium source. The residual lithium hydroxide needs to be removed by washing separately with a washing reagent, and on the other hand, because it is an alkaline substance, it may adversely affect the performance of the material. The amount of the first lithium source used in the first lithium addition is relatively small, and grain boundary fusion can be achieved by the first calcination, allowing the particles to fuse together. If too much of the first lithium source is used, lithium precipitation is likely to occur in some crystal lattices during the first grinding process, and the vacancies created after lithium precipitation are difficult to fill with the second lithium source during the second lithium replenishment. Furthermore, by using a method of adding lithium in two stages, the reaction between materials can be made more thorough. If the first lithium source and the precursor are reacted first and the first pulverization is performed, it is possible to improve the contact area between the second mixture and the second lithium source, and to make the distribution of lithium in the third mixture more uniform.

[0077] The temperature for the second firing may be between 800°C and 950°C, and may be, for example, 800°C, 820°C, 850°C, 880°C, 900°C, 920°C, or 950°C, or any other value within the range of 800°C to 950°C.

[0078] The second firing time can be between 4 and 6 hours, and may be, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, or 6 hours, or any other value within the range of 4 to 6 hours.

[0079] The second firing can also be carried out under an oxygen-containing atmosphere. For example, the oxygen content in the oxygen-containing atmosphere may be 20 wt% or more, such as 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 100 wt%. In several selectable configurations, the oxygen content in the oxygen-containing atmosphere is 80 wt% or more.

[0080] In the process of preparing a single-crystal ternary cathode material, if the single-crystal ternary cathode material contains doping elements, in several selectable configurations, a precursor of the single-crystal ternary cathode material, a first lithium source, and a doping reagent providing the doping elements are mixed, followed by a first calcination. In several selectable configurations, a second mixture, a second lithium source, and a doping reagent providing the doping elements are mixed, followed by a second calcination.

[0081] In the process of preparing a single-crystal ternary cathode material, if the single-crystal ternary cathode material contains a coating element, the preparation method further includes the step (5) of mixing a fourth mixture with a coating reagent that provides the coating element, followed by a third firing.

[0082] In several selectable configurations, the temperature of the third firing may be between 500°C and 700°C, for example, 500°C, 550°C, 600°C, 650°C, or 700°C, or any other value within the range of 500°C to 700°C.

[0083] The time for the third firing can be between 4 and 6 hours, and may be, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, or 6 hours, or any other value within the range of 4 to 6 hours.

[0084] The third firing can also be performed under an oxygen-containing atmosphere. For example, the oxygen content in the oxygen-containing atmosphere may be 20 wt% or more, such as 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 100 wt%. In several selectable configurations, the oxygen content in the oxygen-containing atmosphere is 80 wt% or more.

[0085] Furthermore, this disclosure provides a cathode plate, the active material in the cathode plate, comprising a single-crystal ternary cathode material according to any one of the embodiments described above.

[0086] In several selectable configurations, the initial discharge ratio capacity at 0.1C corresponding to the positive electrode plate is 171.0 mAh / g or greater, and can be, for example, 171.6 mAh / g to 203.4 mAh / g, such as 171.6 mAh / g, 181.7 mAh / g, 183.5 mAh / g, 187.2 mAh / g, 187.5 mAh / g, 188.5 mAh / g, 190.3 mAh / g, 190.9 mAh / g, 193.4 mAh / g, 193.7 mAh / g, 198.8 mAh / g, 201.7 mAh / g, 202.2 mAh / g, or 203.4 mAh / g.

[0087] In several selectable configurations, the capacitance retention rate after 50 cycles at 0.1C corresponding to the positive plate is 89.2% or higher, and can be, for example, 89.2% to 99.4%, such as 89.2%, 91.7%, 92.2%, 92.5%, 93.8%, 94.3%, 94.6%, 95.2%, 95.4%, 95.9%, 97.4%, 97.7%, 98.0%, or 99.4%.

[0088] In several selectable configurations, the initial discharge ratio capacity at 1C corresponding to the positive electrode plate is 148.3 mAh / g or greater, and can be, for example, 148.3 mAh / g to 173.9 mAh / g, such as 148.3 mAh / g, 158.8 mAh / g, 159.3 mAh / g, 159.8 mAh / g, 165.1 mAh / g, 165.3 mAh / g, 168.9 mAh / g, or 173.9 mAh / g.

[0089] In several selectable configurations, the initial discharge ratio capacity at 5C corresponding to the positive electrode plate is 125.8 mAh / g or greater, and can be, for example, 125.8 mAh / g to 152.2 mAh / g, such as 125.8 mAh / g, 136.9 mAh / g, 139.5 mAh / g, 140.0 mAh / g, 144.5 mAh / g, 145.8 mAh / g, 148.9 mAh / g, or 152.2 mAh / g.

[0090] This disclosure further provides a battery cell, which includes the positive electrode plate described above.

[0091] For example, the battery cells described above can be used in electrical devices such as vehicles, ships, or airplanes, but are not limited to these applications.

[0092] This disclosure further provides a battery including the battery cells described above.

[0093] This disclosure further provides electrical devices, which include the battery cells and / or batteries described above. Exemplary examples of electrical devices include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric cars, electric vehicles, ships, and aircraft. Electric toys can be stationary or mobile and include, for example, game consoles, electric car toys, electric boat toys, and electric airplane toys. Aircraft include, for example, airplanes, rockets, space shuttles, and spacecraft.

[0094] The features and performance of the present disclosure will be described in more detail below with reference to the examples provided.

[0095] Example 1 This embodiment provides a single-crystal ternary cathode material. The preparation process for this single-crystal ternary cathode material includes the following steps.

[0096] Step (1): The precursor of the single-crystal ternary cathode material and the first lithium source were mixed, then uniformly polished, and the first firing was performed to obtain the first mixture.

[0097] The precursor of the single-crystal ternary cathode material is nickel-cobalt-manganese hydroxide precursor Ni 0.5 Co 0.2 Mn 0.3 The substance was (OH)2. The first lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Mn in the nickel-cobalt-manganese hydroxide precursor to the number of moles of Li in the first lithium source was 1:0.55. The first calcination was performed at 700°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 2 hours.

[0098] Step (2): The first mixture was transferred to water at a temperature of 30°C while maintaining the temperature above 600°C for the first grinding, followed by filtration and drying to obtain the second mixture.

[0099] The first grinding was carried out for 10 minutes under stirring conditions of 150 rpm, and drying was performed for 12 hours under conditions of 100°C.

[0100] Step (3): After mixing the second mixture with the second lithium source, a second calcination was performed to obtain the third mixture.

[0101] The second lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Mn in the second mixture to the number of moles of Li in the second lithium source was 1:0.53. That is, the ratio of the total amount of lithium elements in the first and second lithium sources to the total amount of transition metal elements in the second mixture was 1.08:1. The second firing was carried out at 900°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 5 hours.

[0102] Step (4): The third mixture was subjected to a second grinding using an air-jet grinding method to obtain the fourth mixture (single-crystal ternary cathode material).

[0103] Example 2 This embodiment differs from Embodiment 1 in the following respects: The ratio of the total number of moles of Ni, Co, and Mn in the nickel-cobalt-manganese hydroxide precursor to the number of moles of Li in the first lithium source was 1:0.4.

[0104] Example 3 This embodiment differs from Embodiment 1 in the following respects: The ratio of the total number of moles of Ni, Co, and Mn in the nickel-cobalt-manganese hydroxide precursor to the number of moles of Li in the first lithium source was 1:0.7.

[0105] Example 4 This embodiment differs from Embodiment 1 in the following respects: In step (2), the stirring time was 5 minutes.

[0106] Example 5 This embodiment differs from Embodiment 1 in the following respects: In step (2), the stirring time was 20 minutes.

[0107] Example 6 This embodiment provides a single-crystal ternary cathode material. The preparation process for this single-crystal ternary cathode material includes the following steps.

[0108] Step (1): The precursor of the single-crystal ternary cathode material and the first lithium source were mixed, then uniformly polished, and the first firing was performed to obtain the first mixture.

[0109] The precursor of the single-crystal ternary cathode material is the nickel-cobalt-aluminum hydroxide precursor, Ni 0.821 Co 0.154 Al 0.025The substance was (OH)2. The first lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Al in the nickel-cobalt-aluminum hydroxide precursor to the number of moles of Li in the first lithium source was 1:0.5. The first calcination was performed at 700°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 1 hour.

[0110] Step (2): This was the same as Step (2) of Example 1.

[0111] Step (3): After mixing the second mixture with the second lithium source, a second calcination was performed to obtain the third mixture.

[0112] The second lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Al in the second mixture to the number of moles of Li in the second lithium source was 1:0.55. That is, the ratio of the total number of moles of lithium elements in the first and second lithium sources to the total number of moles of transition metal elements in the second mixture was 1.05:1. The second firing was carried out at 800°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 6 hours.

[0113] Step (4): This was the same as step (4) of Example 1.

[0114] Example 7 This embodiment provides a single-crystal ternary cathode material. The preparation process for this single-crystal ternary cathode material includes the following steps.

[0115] Step (1): The precursor of the single-crystal ternary cathode material and the first lithium source were mixed, then uniformly polished, and the first firing was performed to obtain the first mixture.

[0116] The precursor of the single-crystal ternary cathode material is nickel-cobalt-manganese hydroxide precursor Ni 0.8 Co 0.1 Mn 0.1The precursor was (OH)2. In this precursor, the molar ratio of Ni, Co, and Mn was 8:1:1. The first lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Mn in the nickel-cobalt-manganese hydroxide precursor to the number of moles of Li in the first lithium source was 1:0.7. The first calcination was performed at 650°C in an oxygen-containing atmosphere (oxygen content was 80 wt%) for 3 hours.

[0117] Step (2): The first mixture was transferred to water at a temperature of 5°C while maintaining the temperature above 550°C for the first grinding, followed by filtration and drying to obtain the second mixture.

[0118] The first grinding was carried out for 15 minutes under stirring conditions of 100 rpm, and drying was performed for 12 hours under conditions of 100°C.

[0119] Step (3): The second mixture, the second lithium source, and zirconia were mixed and uniformly polished, and then a second firing was performed to obtain the third mixture.

[0120] The second lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Mn in the second mixture to the number of moles of Li in the second lithium source was 1:0.4. That is, the ratio of the total number of moles of lithium elements in the first and second lithium sources to the total number of moles of transition metal elements in the second mixture was 1.1:1. The amount of zirconia used was 1000 ppm of the mass of the nickel-cobalt-manganese hydroxide precursor. The second calcination was carried out at 950°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0121] Step (4): The third mixture was subjected to a second grinding using an air-jet grinding method to obtain the fourth mixture (single-crystal ternary cathode material).

[0122] Example 8 This embodiment provides a single-crystal ternary cathode material. The preparation process for this single-crystal ternary cathode material includes the following steps.

[0123] Step (1): The precursor of the single-crystal ternary cathode material and the first lithium source were mixed, then uniformly polished, and the first firing was performed to obtain the first mixture.

[0124] The precursor of the single-crystal ternary cathode material is nickel-cobalt-manganese hydroxide precursor Ni 0.34 Co 0.33 Mn 0.33 The precursor was (OH)2. In this precursor, the molar ratio of Ni, Co, and Mn was 1:1:1. The first lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Mn in the nickel-cobalt-manganese hydroxide precursor to the number of moles of Li in the first lithium source was 1:0.6. The first calcination was performed at 750°C in an oxygen-containing atmosphere (oxygen content was 20 wt%) for 2 hours.

[0125] Step (2): The first mixture was transferred to water at a temperature of 50°C while maintaining the temperature above 650°C for the first grinding, followed by filtration and drying to obtain the second mixture.

[0126] The first grinding was carried out for 15 minutes under stirring conditions of 200 rpm, and drying was performed for 12 hours under conditions of 100°C.

[0127] Step (3): The second mixture was mixed with the second lithium source and aluminum oxide, and after uniform polishing, a second firing was performed to obtain the third mixture.

[0128] The second lithium source was lithium hydroxide. The ratio of the total number of moles of Ni, Co, and Mn in the second mixture to the number of moles of Li in the second lithium source was 1:0.45. That is, the ratio of the total number of moles of lithium elements in the first and second lithium sources to the total number of moles of transition metal elements in the second mixture was 1.05:1. The amount of aluminum oxide used was 1000 ppm of the mass of the nickel-cobalt-manganese hydroxide precursor. The second calcination was carried out at 900°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 5 hours.

[0129] Step (4): The third mixture was subjected to a second grinding using an air-jet grinding method to obtain the fourth mixture (single-crystal ternary cathode material).

[0130] Example 9 This embodiment differs from Example 1 in the following respects: it further includes step (5) of mixing the fourth mixture with aluminum oxide, uniformly polishing it, and then performing a third firing.

[0131] The amount of aluminum oxide used was 1 wt% of the mass of the fourth mixture. The third firing was carried out at 500°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0132] Example 10 This embodiment differs from Example 2 in the following respects: it further includes step (5) of mixing the fourth mixture with aluminum oxide, uniformly polishing it, and then performing a third firing.

[0133] The amount of aluminum oxide used was 1 wt% of the mass of the fourth mixture. The third firing was carried out at 500°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0134] Example 11 This embodiment differs from Example 4 in the following respects: it further includes step (5) of mixing the fourth mixture with aluminum oxide, uniformly polishing it, and then performing a third firing.

[0135] The amount of aluminum oxide used was 1 wt% of the mass of the fourth mixture. The third firing was carried out at 700°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0136] Example 12 This embodiment differs from Example 5 in the following respects: it further includes step (5) of mixing the fourth mixture with aluminum oxide, uniformly polishing it, and then performing a third firing.

[0137] The amount of aluminum oxide used was 1 wt% of the mass of the fourth mixture. The third firing was carried out at 700°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0138] Example 13 This embodiment differs from Example 6 in the following respects: it further includes step (5) of mixing the fourth mixture with H3BO3, uniformly polishing it, and then performing a third firing.

[0139] The amount of H3BO3 used was 1 wt% of the mass of the fourth mixture. The third firing was carried out at 600°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 6 hours.

[0140] Example 14 This embodiment differs from Example 7 in the following respects: it further includes step (5) of mixing the fourth mixture with aluminum oxide, uniformly polishing it, and then performing a third firing.

[0141] The amount of aluminum oxide used was 1 wt% of the mass of the fourth mixture. The third firing was carried out at 700°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0142] Comparative Example 1 This comparative example differs from Example 1 in the following respects: The nickel-cobalt-manganese hydroxide precursor and the lithium source (lithium hydroxide) were mixed directly in one step, then uniformly polished, and then calcined. After calcination, air-jet pulverization was performed.

[0143] The nickel-cobalt-manganese hydroxide precursor was the same as the precursor used in Example 1. The ratio of the total number of moles of Ni, Co, and Mn in the nickel-cobalt-manganese hydroxide precursor to the number of moles of Li in the lithium source was 1:1.08. Calcination was carried out at 900°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 12 hours.

[0144] Comparative Example 2 This comparative example differs from Example 1 in the following respect: Step (2) was omitted.

[0145] Specifically, the first mixture obtained in step (1) of Example 1 was directly mixed with the second lithium source, followed by a second calcination, and then step (4) of Example 1 was performed.

[0146] Comparative Example 3 This comparative example differs from Comparative Example 1 in the following respects: it further includes the step of mixing the material after air-jet pulverization with aluminum oxide, uniformly polishing it, and then firing it at 500°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0147] The amount of aluminum oxide used was 1 wt% of the mass of the material after air-jet pulverization.

[0148] Comparative Example 4 This comparative example differs from comparative example 2 in the following respects. The material after air-jet pulverization was mixed with aluminum oxide, uniformly polished, and then fired at 500°C in an oxygen-rich atmosphere (oxygen content was 98 wt%) for 4 hours.

[0149] The amount of aluminum oxide used was 1 wt% of the mass of the material after air-jet pulverization.

[0150] Comparative Example 5 This comparative example differs from Example 1 in the following respects. The first grinding was performed by dry grinding after the first mixture was cooled to room temperature.

[0151] Test example (1) Using the single-crystal ternary cathode materials obtained in Examples 1 to 5 and Comparative Example 1 as examples, X-ray diffraction evaluation was performed on the obtained single-crystal ternary cathode materials, and the obtained XRD patterns are shown in Figure 1.

[0152] As shown in Figure 1, the diffraction peaks of the XRD patterns of all single-crystal materials perfectly match the standard card for LiNiO2 (PDF#74-0919), indicating that all synthesized materials have a hexagonal α-NaFeO2 layered structure (R-3m space group) and are free from other impurity phases. Furthermore, as shown in Figure 1, the two sets of peaks (006) / (102) and (108) / (110) are remarkably separated, indicating that all synthesized materials have good crystallinity and a highly ordered layered structure.

[0153] Furthermore, the XRD patterns were fitted using MDI.Jade.6.0, and the crystal lattice parameters were calculated. The results are shown in Table 1.

[0154] [Table 1]

[0155] As shown in Table 1, the c / a ratio of the single-crystal materials prepared in each example was greater than 4.899, indicating that all materials had a good layered structure. Furthermore, the R values ​​corresponding to each of Examples 1 to 5 were all higher than those of Comparative Example 1, indicating that the degree of irregular arrangement of lithium nickel in the materials obtained in Examples 1 to 5 was lower than that of the material obtained in Comparative Example 1.

[0156] (2) Using the single-crystal ternary cathode materials obtained in Example 1, Example 10, and Comparative Example 1 as examples, each single-crystal ternary cathode material was observed with a scanning electron microscope, and the resulting SEM images are shown in Figure 2. (A) in Figure 2 is the SEM image of the single-crystal ternary cathode material obtained in Example 1, (B) in Figure 2 is the SEM image of the single-crystal ternary cathode material obtained in Example 10, and (C) in Figure 2 is the SEM image of the single-crystal ternary cathode material obtained in Comparative Example 1.

[0157] As shown in Figure 2, the single-crystal ternary cathode materials obtained in Example 1 and Example 10 had better circularity and rounded edges and corners than the single-crystal ternary cathode material obtained in Comparative Example 1. Furthermore, the circularity of the single-crystal ternary cathode material obtained in Example 10 was better than that of Example 1.

[0158] (3) Performance measurement ○1. Apparent physical quantities were measured for the uncoated single-crystal ternary cathode materials prepared in each of Examples 1-8, Comparative Examples 1-2, and Comparative Example 5. Then, electrodes were prepared using each of the single-crystal ternary cathode materials, and the surface roughness of each electrode was measured. The measurement results are shown in Table 2.

[0159] The measurement method was as follows:

[0160] A. The microstructure of the sample was observed using a JEOL JSM-6490LV scanning electron microscope, and scanning electron microscope images were obtained. The sample was prepared as follows: A conductive adhesive for scanning electron microscopy was attached to the sample stage, the sample powder was taken with a toothpick, and the powder was lightly dropped onto the conductive adhesive by gently shaking the arm. Any powder that was not firmly adhered was then blown away using an ear-washing ball, and the above procedure was repeated until the surface of the conductive adhesive was covered with one layer of powder.

[0161] Then, using ImageJ, shape analysis was performed on individual particles in scanning electron microscope images, and parameters such as particle number, area, perimeter, and circularity were collected. Each single-crystal material sample had 50 measurements, which were randomly selected.

[0162] Using a B.LS13320 laser particle size analyzer, the particle size and particle size distribution of the single-crystal ternary cathode material were analyzed. Specifically, using a wet dispersion technique, the sample was uniformly dispersed by mechanical stirring, aggregated particles were thoroughly dispersed by ultrasonic high-frequency vibration, and large and small particles were uniformly distributed throughout the circulation system using an electromagnetic circulation pump.

[0163] The surface roughness Ra of the electrodes was measured using the C.SJ-210 surface roughness measuring device. For various electrode samples, different locations were selected, and measurements were taken three times for each sample. The average value was then calculated.

[0164] The electrode preparation method was as follows: Single-crystal ternary cathode material, conductive carbon black, and PVDF were weighed in a mass ratio of 8:1:1, thoroughly polished, placed in a container, an appropriate amount of NMP solvent was added, and the mixture was stirred in a stirrer for 24 hours to form a uniform slurry. Using a wet film deposition apparatus, the prepared slurry was uniformly applied to clean aluminum foil, with a coating amount of 2.5 ± 0.05 mg / cm². 2 Then, it was placed in a vacuum drying box at 100°C and dried for 24 hours until no more material was stuck to it.

[0165] [Table 2]

[0166] As can be seen from Table 2, by adjusting the preparation process conditions, single-crystal materials with different apparent factors can be obtained.

[0167] ○2. Electrochemical performance measurements were performed on the uncoated single-crystal ternary cathode materials prepared in each of Examples 1-8, Comparative Examples 1-2, and Comparative Example 5.

[0168] As a measurement method, the electrode corresponding to C in ○1 above was further punched out to form a circular electrode plate with a diameter of 12 mm, a metallic lithium circular sheet was used as the negative electrode, Celgard 2300 was used as the separator, and a 1 mol / L LiPF6 solution (the solvent was a mixed solution of EMC, DC, and DMC in a volume ratio of 1:1:1) was used as the electrolyte to assemble a CR2032 type button cell. Rate performance was then evaluated using the LANHECT2001A battery evaluation system, and the results are shown in Table 3.

[0169] [Table 3]

[0170] As can be seen from Table 3, the batteries corresponding to the electrodes prepared with the single-crystal ternary cathode material according to Examples 1 to 8 of this disclosure exhibited high specific capacity, cycle stability, and rate performance.

[0171] ○3. Apparent physical quantities were measured for the coated single-crystal ternary cathode materials prepared in each of Examples 9-13 and Comparative Examples 3-4, and the surface roughness was measured for the prepared electrodes. The measurement method was as described in ○1 above, and the measurement results are shown in Table 4.

[0172] [Table 4]

[0173] As can be seen from Table 4, the coated single-crystal ternary cathode material exhibits differences in hardness and grain size distribution coefficient (D) compared to the uncoated related material. 90 / D 10 Although there was no significant difference in ), the apparent factor was reduced to some extent due to a certain degree of improvement in sphericity, and there is a positive correlation between the apparent factor of the coated single-crystal ternary cathode material and the corresponding surface roughness of the electrode. ○4. The coated single-crystal ternary cathode materials prepared in Examples 9-13 and Comparative Examples 3-4 were each prepared as electrodes, and their electrochemical performance was measured. The measurement method was as described in ○2 above, and the measurement results are shown in Table 5.

[0174] [Table 5]

[0175] As can be seen from Table 5, the batteries corresponding to electrodes prepared with single-crystal ternary cathode materials according to Examples 9-13 of this disclosure exhibited relatively high specific capacity and cycle stability. Electrode plates corresponding to each example and comparative example in ○5.○1 and ○4 were placed in a hydraulic machine and roll-rolled at pressures of 2 MPa, 6 MPa, and 15 MPa, respectively. The relationship between the apparent factor of each single-crystal ternary cathode material and the surface roughness of the electrode plate after pressing at different pressures was statistically analyzed, and the results are shown in Figure 3. The 17 points corresponding to each shaded line in Figure 3 represent the results for 13 examples (Examples 1-13) and 4 comparative examples (Comparative Examples 1-4). As can be seen from Figure 3, both before and after coating, there is a linear positive correlation between the apparent factor of the single-crystal ternary cathode material and the surface roughness of the electrode plate at different roll-rolling pressures.

[0176] As described above, this disclosure provides a single-crystal ternary cathode material having apparent factors that satisfy a specific range. A single-crystal ternary cathode material having apparent factors within this range has a smooth surface and rounded edges and corners, which can contribute to electrodes and batteries using this cathode material having relatively high specific capacity, rate performance, and cycle performance. The preparation method for a suitable single-crystal ternary cathode material is simple, easy to operate, and suitable for mass production. [Industrial applicability]

[0177] The single-crystal ternary cathode material according to this disclosure has a smooth surface with rounded edges and corners, and electrodes using this cathode material exhibit relatively high specific capacity, rate performance, and cycle performance. The method for preparing this single-crystal ternary cathode material is simple, easy to operate, and suitable for mass production. Using this single-crystal ternary cathode material, batteries and electrical devices with excellent electrochemical performance can be prepared.

Claims

1. A single-crystal ternary cathode material, The apparent factor Z of the aforementioned single-crystal ternary cathode material is Z = [Math 1] The apparent factor of the single-crystal ternary cathode material is 1.1 to 3.

0. x = D ９０ / D １０ And satisfying 2 ≤ x ≤ 5, D ９０ D is the particle size corresponding to the volume-based cumulative particle size distribution of the single-crystal ternary cathode material when it reaches 90%. １０ This is the particle size corresponding to when the volume-based cumulative particle size distribution of the single-crystal ternary cathode material reaches 10%, and D of the single-crystal ternary cathode material １０ It is 2.4 μm or less, S(D ９０ ) is the number-average circularity, and the number-average circularity is the value obtained by dividing the sum of the circularities of all target particles included in the single-crystalline ternary cathode material by n. The circularity Q = l ２ / l １ . The area and perimeter corresponding to the two-dimensional projection diagram of one target particle are defined as S １ and l １ respectively. The perimeter of a circle having an area S １ is defined as l ２ . The target particles are defined as single-crystalline ternary cathode material particles having a particle size of D ９０ or more in the single-crystalline ternary cathode material. n is the total number of the target particles included in the single-crystalline ternary cathode material. H is hardness, and H = [Math 2] ×100%, and here, D １０ ' is the particle size corresponding to when the volume-based cumulative particle size distribution of the fres material reaches 10%, the fres material is a material obtained by pressing the single-crystal ternary cathode material at a pressure of 200 MPa, and the D of the single-crystal ternary cathode material １０ ' is 2.3 μm or less. A single-crystal ternary cathode material characterized by the following features.

2. The aforementioned single-crystal ternary cathode material is Feature 1: D of the single-crystal ternary cathode material ９０ The size is 8.6 μm or less, Feature 2: The H content of the single-crystal ternary cathode material is 80% or more, Feature 3: S(D) of the single-crystal ternary cathode material ９０ ) is 0.9 or less, Includes at least one of the features 1 to 3. The single-crystal ternary cathode material according to feature 1.

3. The apparent factor of the aforementioned single-crystal ternary cathode material is 1.1634 to 2.9571. and / or, x of the single-crystal ternary cathode material is 2.36 to 3.88, and / or the D of the single-crystal ternary cathode material ９０ The size ranges from 5.01 μm to 8.56 μm. and / or the D of the single-crystal ternary cathode material １０ The size is between 1.81 μm and 2.34 μm. and / or, the H content of the single-crystal ternary cathode material is 81% to 96%, and / or the S(D) of the single-crystal ternary cathode material. ９０ ) is 0.68 to 0.87, and / or the D of the single-crystal ternary cathode material １０ The size is between 1.57 μm and 2.25 μm. The single-crystal ternary cathode material according to feature 2.

4. The aforementioned single-crystal ternary cathode material is Feature 4: The particle size of the single-crystal ternary cathode material is 20 μm or less, Feature 5: The general formula of the single-crystal ternary cathode material is Li ｄ Ni ａ Co ｂ M ｃ M' １－ａ－ｂ－ｃ O ２ The following conditions are met: 0.95 ≤ d < 1.1, a > 0, b > 0, c > 0, 0.95 ≤ (a + b + c) ≤ 1, M comprises at least one of Al and Mn, M' comprises at least one of a doping element and a coating element, and the doping element and the coating element are each independently at least one selected from Zr, Sr, Mo, Ba, W, B, Ti, Mg, Li, C, F, Si, Ca, Cu, La, P, Ce, Bi, In, Nb, and Y. Feature 6: In the single-crystal ternary cathode material, the unit cell parameter c and the unit cell parameter a satisfy c / a ≥ 4.899, Feature 7: (003) crystal plane diffraction peak intensity I of the single-crystal ternary cathode material （００３） (104) Crystal plane diffraction peak intensity I （１０４） However, I （００３） / I （１０４） The condition that ≥ 1.51 is met, Feature 8: The surface roughness Ra of the electrode plate corresponding to the single-crystal ternary cathode material is 2.20 μm or less, It further includes at least one of features 4 to 8. A single-crystal ternary cathode material according to any one of claims 1 to 3.

5. The doping reagent providing the doping element comprises at least one of the oxides, fluorides, carbonates, hydroxides, nitrides, borides, and nitrates corresponding to the doping element. and / or, the coating reagent providing the coating element comprises at least one of the oxides, fluorides, carbonates, hydroxides, nitrides, borides, and nitrates corresponding to the coating element. The single-crystal ternary cathode material according to feature 4.

6. The surface roughness Ra of the electrode plate corresponding to the single-crystal ternary cathode material is 0.86 μm to 2.12 μm. The single-crystal ternary cathode material according to feature 4 or 5.

7. A method for preparing a single-crystal ternary cathode material according to any one of claims 1 to 6, The first step involves mixing a precursor of a single-crystal ternary cathode material with a first lithium source, followed by a first firing to obtain a first mixture. The first mixture is rapidly transferred to water at a high temperature and stirred to perform the first grinding, thereby obtaining a second mixture. The steps include: mixing the second mixture with the second lithium source and then performing a second calcination to obtain a third mixture; The process includes the step of performing a second grinding of the third mixture to obtain a fourth mixture. A method for preparing a single-crystal ternary cathode material, characterized by the following features.

8. The preparation of the first mixture is as follows: Feature 1: The type of precursor of the single-crystal ternary cathode material is a hydroxide precursor, Feature 2: The ratio of the total molar amount of transition metal elements in the precursor of the single-crystal ternary cathode material to the molar amount of lithium elements in the first lithium source is 1:0.4 to 1:0.7, Feature 3: The temperature of the first firing is 650°C to 750°C, Feature 4: The first firing time is 1 to 3 hours, Feature 5: The first firing is carried out in an oxygen-containing atmosphere, Includes at least one of the features 1 to 5 The preparation method according to feature 7.

9. The precursor of the single-crystal ternary cathode material comprises nickel-cobalt-manganese hydroxide or nickel-cobalt-aluminum hydroxide. The preparation method according to feature 8.

10. The first crushing is Feature 6: The first pulverization is achieved by the thermal expansion effect, Feature 7: The water temperature used for the first grinding is above 0°C and below 50°C. Feature 8: The rotation speed of the stirring during the first grinding is 100 rpm to 200 rpm, Feature 9: The stirring time for the first grinding is 5 to 20 minutes, It includes at least one of features 6 to 9, And / or, the second grinding is carried out using an air-jet grinding method. The preparation method according to any one of claims 7 to 9, characterized by the features described herein.

11. The time for transferring the first mixture to water at a high temperature is 30 minutes or less. The preparation method according to any one of claims 8 to 10.

12. The preparation of the third mixture is as follows: Feature 10: The ratio of the total molar amount of lithium elements in the first lithium source and the second lithium source to the total molar amount of transition metal elements in the second mixture is 1.05:1 to 1.1:1, Feature 11: The temperature of the second firing is 800°C to 950°C, Feature 12: The second firing time is 4 to 6 hours, Feature 13: The second firing is carried out in an oxygen-containing atmosphere, It includes at least one of the features 10 to 13. The preparation method according to any one of claims 7 to 11, characterized by the features described herein.

13. If the single-crystal ternary cathode material contains a doping element, the precursor of the single-crystal ternary cathode material, the first lithium source, and the doping reagent providing the doping element are mixed and then fired for the first time, or the second mixture, the second lithium source, and the doping reagent providing the doping element are mixed and then fired for the second time. Alternatively, if the single-crystal ternary cathode material contains a coating element, the preparation method further includes mixing the fourth mixture with a coating reagent that provides the coating element, followed by a third firing. The preparation method according to any one of claims 7 to 12, characterized by the features described herein.

14. In the first firing, the oxygen gas content in the oxygen-containing atmosphere is 20 wt% or more, and / or the second firing is carried out in an oxygen-containing atmosphere with an oxygen gas content of 20 wt% or more, and / or the third firing is carried out in an oxygen-containing atmosphere with an oxygen gas content of 20 wt% or more. The preparation method according to feature 13.

15. It is a positive electrode plate, The active material in the positive electrode plate includes the single-crystal ternary positive electrode material described in any one of claims 1 to 6. A positive electrode plate characterized by the following features.

16. The positive electrode plate is Feature 9: The initial discharge ratio capacity at 0.1C corresponding to the positive electrode plate is 171.0 mAh / g or more, Feature 10: The capacitance retention rate of the positive electrode plate after 50 cycles at 0.1C is 89.2% or higher, Feature 11: The initial discharge ratio capacity at 1C corresponding to the positive electrode plate is 148.3 mAh / g or more, Feature 12: The initial discharge ratio capacity at 5C corresponding to the positive electrode plate is 125.8 mAh / g or more, Includes at least one of features 9 to 12 The positive electrode plate according to claim 15.

17. Includes the positive electrode plate according to claim 15 or 16 A battery cell characterized by the following features.

18. Includes the battery cell described in claim 17 A battery characterized by the following features.

19. Includes a battery cell according to claim 17 or a battery according to claim 18 An electrical device characterized by the following features.

20. An electrical device, The aforementioned electrical devices include mobile phones, tablets, laptop computers, electric toys, power tools, electric vehicles, electric cars, ships, or aircraft. The electrical device according to feature 19.

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